Dryer repair

Dryer(tumble dryer) is a household appliance for drying clothes, shoes, hats etc. Tumble dryers consist of a rotating drum through which heated air circulates to evaporate the moisture of the laundry load. Tumble dryer rotates to maintain air space between items.

There are two types of dryers:

1. Gas, which is fueled by natural gas or liquid propane. Require professional installation; operating cost is often 1/2 of an electric dryer; dries clothes faster and is gentler on fabric.
2. Electric. Operates on 240 volts current and easy to install by yourself; less expensive than a gas dryer.

Dryer Operation basics:

• Power Start:

Voltage needs to be present in order for the dryer to initiate the start process.

• Tumble:

Drive motor Will need to be energized, in order for the drum to start moving the clothes.

• Heat:

On Gas models Gas supply needs to present, and Voltage needs to be supplied to igniter in order to open gas valves. On Electric models a 2nd set of voltage needs to be supplied to supply voltage to the heating circuit (240v).

• Air Flow: 

In order for clothes to dry, Air flow will need to be present and be a main factor. Heat needs to be extracted from the dryer in order for clothes to get fully dry.

Key things that need to happen:

1. We need to have our source Voltage, 120v supplied to the machine, or 240v on Electric models.
2. Door switch. Will need to be closed. Door switch is needed to complete the circuit to allow the motor to start.
3. Start Switch. In order for the dryer to start the start switch needs to close. Remove the switch, push it and check to make sure continuity is present.
4. Belt. In order for the Dryer to start, the Belt has to have tension and be attached to the drum. This allows the belt switch to be engaged. If the belt switch is not engaged the drive motor will not start.
5. Thermal Fuse. On Electric models a thermal fuse needs to be closed (have continuity) in order for the dryer to start. On electric models the thermal fuse is in line with the motor circuit. Thermal fuse is normally found on the exhaust port of dryer.
6. Motor and Blower wheel. In order for the dryer to tumble or start, the motor will need to run. If a humming noise is heard, never overlook a jammed blower wheel. The blower wheel is attached to the motor.
7. Timer or Control board: Lastly, the timer or control board needs to supply voltage to key components in order for them to start. Timers normally last in order to fail, Control boards on the other hand are common for relays to get damaged on control boards.

Dryer repair stages: Tumble Stage

One: Drive motor.

Needs to have 120v sent from the Control board/ Timer to activate motor movement. Hardly fails, if it does, it will also give a loud hum and will get very HOT don’t touch.

Two: Door Switch.

If your door switch is not working you will not get any motor movement, a very important piece on a washer. A door switch will always complete the circuit to your motor

Three: Belt.

Belt has to be installed with grooves facing down, also Belt needs to be attached to the Idler pulley, where it creates tension so the belt switch is activated. Without the belt switch being activated the drive motor will not run.

Four: Thermal fuse.ONLY ON ELECTRIC DRYERS 

Thermal fuse is a safety device that monitors the temperature on the exhaust port of the dryer. When it fails the thermal fuse will read open or no continuity.

Five: Dryer Rollers.

Dryer rollers are designed to help turn the dryer drum. Normally there are two rollers in the rear and two in the front that help stabilize the drum. As the drum rotates, the rollers help rotate the drum.

Six: Idler Pulley.

Idler pulley helps the dryer belt turn the drum. The idler pulley on a dryer keeps tension on the dryer belt so it can grab that big drum and turn it. These pulleys have a bearing in the middle that sometimes wears down with age. Often, when the dryer idler pulley begins to fail it will make a high pitched squeaky noise that is very annoying.

Dryer repair stages: Heat Stage

One: Control board/ Timer.

Needs to send 120v or (240v for electric dryers) to to activate the heating circuit.

Two: Door Switch.

If your door switch or door lock is not working you will not get any motor movement, a very important piece on a Dryer. A door switch will always complete the circuit to your motor

Three: Source Voltage.

ELECTRIC DRYER needs 240v to run the heating circuit, normally on 230-amp breakers in the fuse box. Always remember the dryer will run with only 120v but it will not cycle the heating circuit.

Four: Thermostats.

Dryers have a series of thermostats, we have a cycling thermostat and thermal fuse that monitors the temperature in the exhaust, then we have a high limit and thermal cut off that monitors the temperature on the heating circuit side. If any of those thermostats are open (no continuity) you will not get the heating circuit to work.

Five: Heating Element.

ELECTRIC DRYERS Heating element is the main heat source for the dryer. If the dryer is not heating, make sure to check to see if the heating element has continuity.

Six: Igniter. 

GAS DRYERS, gas dryers have igniter that will glow to a certain temperature to activate the gas valve to let the gas enter the dryer. A weak igniter or open igniter will never pull enough amperage to open the gas valve, Checking a igniter is simple. Set the meter to Ohm and check resistance, normally around 13 ohms, If it reads OL igniter is bad.

Seven: Gas Coils/ Gas valve.

On the gas valve are one or two coils (solenoids) used to open and close the valve to c-ontrol the flow of gas. If a coil fails, gas will not flow and the dryer will have no heat, Check each coil with Ohms or resistance, if you read OL or a drastic change in readings between both coils. Replace them.

Eight: Flame sensor. 

Located on the burner funnel, the flame sensor detects the igniter temperature. When the igniter is hot enough to light the gas burner, the flame sensor shuts off the igniter, the coils open the gas valves, and the burner ignites. If the flame sensor fails, it won’t shut off the igniter, gas won’t flow to the burner, and the dryer won’t heat. Easy to check, use your meter to set continuity and check between both pins.

Nine: Motor.

Very unlikely to fail, but may be a possibility, the motor has a centrifugal switch that carries another leg of voltage to the heating circuit. If that centrifugal switch is damaged on the motor the unit will not heat.

Dryer repair stages: Air Flow Stage

One: Blower wheel. 

The Blower wheel is attached to the motor shaft. When the blower wheel turns it’s extracting the heat from the dryer to the outside of the house.

Two: Lint Screen. 

Very important that the lint screen is cleaned after every use. The lint screen is made of a mesh that collects lint from clothes. If the mesh is clogged and air flow is restricted through mesh, air flow cannot travel towards the blower wheel.

Three: Dryer Exhaust. 

Most common repair on a dryer. The exhaust is a very key component on the dryer. If that air cannot escape to the outside, the moisture will stay in the machine. This can cause a variety of problems, Not drying the clothes correctly or blowing a thermostat for clogged vents.